Carburetor construction



Nov. 11, 1952 Filed Jan. 19, 1949 J R STUD/V/CKV IN V EN TOR.

A TTOR NEVS Patented Nov. 11, 1952 oARBURE'roR CONSTRUCTION John P. Studnicky, Dearborn, and Alphonse S. Rick, Detroit, Mich., assignors to Ford Motor Company, Dearborn, Mich a corporation of Delaware Application January 19, 1949, Serial No. 71,708

i 4 Claims. (01. 277-42) This invention is concerned with internal combustion engine carburetors and more particularly with a control system for such carburetors. There has been a pronounced tendency in recent years towards thesimplification of vehicular controls and the elimination of as many controls as possible. In line with this tendency, the throttle lever has been deleted from the dash board. With this change, the only carburetor controls available to the driver are the choke lever and the foot throttle. This control situation is inadequatein many situations. As typical of such may be cited occasions where it is desired to rapidly idle the motor to assist in starting the automobile up a grade, or to rapidly warm up the engine.

It has been common practise in the automotive industry to interconnect the choke valve and the throttle valve so that the throttle valve is partially opened by the initial movement of the choke valve towards the closed position. This is to insure easy starting. With this structure and in the absence of a hand throttle, there is a tendency on the part of drivers to secure rapid idling by partially closing the choke in order to secure a partial opening of the throttle valve. This practise results in the operation of the engine with a very rich mixture with the inevitable waste of fuel and washing of lubricant from the cylinder walls. To enable an operator to selectively use the choke lever either to obtain fast idling or as a conventional choke this invention has been developed.

This invention is probably best understood by a study of the drawings in which;

Figure l is a side elevation of a downdraft carburetor employing applicants invention,

Figure 2 is a cross section along the line 22 in Figure 1,

Figure 3 is a schematic representation of the throttle-choke linkage in the normal or driving position,

Figure 4 is a schematic representation of this linkage in the fast idling position, and

Figure 5 is a schematic representation of this linkage in the choked position.

In the carburetor shown in Figure l, the air is inducted at the uppermost part and sweeps down through the device and enters an intake manifold (not shown) which is bolted against face It. The passage of air through the carburetor is subject to the control of two butterfly type valves, a choke valve which pivots on pin II and a throttle valve which pivots on pin I2. The throttle valve is of course controlled by the accelerator pedal. Motion "is imparted to the throttle valve through ball l3 mounted on plate l4 which is securely riveted to pin |2. Face l5 of plate l4 abuts against adjustable set screw 6 to accurately regulate the setting of the throttle valve in the closed or idling position. Similarly, the movement of the throttle valve in the fully open position is limited when face IT on plate |4' abuts stop l8.

The choke valve, is spring biased into the closedposition and normally is held open against this spring bias by the contact of arm I 9 with tine 20 of bifurcated lever 2|. This arm |9 is mounted on disc 22 which in turn is riveted to pin upon which is mounted the choke valve. Lever 2| and choke control arm' 23 are both pivoted on stub shaft 24 as shown in .Figure 2 and are secured against axial motion by screw 25.

As can be best seen in Figure 2, a pin 26 is mounted rigidly in lever 2|. This pin is received in slot 21 in arm 23 (Figure 1). Lever 2| and arm 23 are free to rotate independently of each other within the limits permitted by the coaction of pin 26 and slot 21. Motion is imparted to arm 23 by a manually operated linkage terminating in ball 28.

Lever 23 (Figures 1, 3, 4 and 5) is pivotally mounted on screw 30 and is threaded at 'its lower end to receive adjusting set screw |6 which serves to regulate normal idling speed of the motor. Lever 29 is spring biased to rotate clockwise about screw 30. The upper end of lever 29 is bent at right angles to provide a cam follower 3|. Cam follower 3| coacts with cam face 32 which is part of lever 23. When arm 23 is manually rotated clockwise to permit the choke butterfly valve to close, cam follower 3| rides up cam face 32 and causes lever 29 to rotate counterclockwise. This counterclockwise rotation of lever 29 moves adjusting screw|6 to the right and opens the throttle valve to a position beyond the ordinary idling position.

Three positions of the various linkages are shown in'Figures 3, 4 and 5. Figure 3 is the ordinary idling position in which choke butterfly 33 is in the fully open position and throttle butterfly 34 is in the idling position. In this position, choke butterfly 33 is held in the fully open position against its spring bias by the contact of arm I9 against tine 20.

In the position shown in Figure 4, arm 23 has been rotated clockwise until pin 26 abuts the right rather than the left end of slot 21. This causes cam follower 3| to ride up cam face 32 and so rotate lever 29 counterclockwise against its spring bias. This moves adjusting screw [6 to the right and moves throttle butterfly 34 to a position more open than the usual idling position. For purposes of comparison, the normal idling position of throttle butterfly 34 has been indicated in dotted lines. While, in this position, movement. of lever 26 by the spring. bias of the choke butterfly 33 is prevented by a ball and socket detent or other frictional restraining.

mechanism (not shown).

Figure differs from Figure 4 in thatthearm 23 has been manually moved, to the full choke position. When this happens, pin, Z'G'engages the slot 21 and rotates lever 2| clockwise and per-- mits the spring bias of choke butterfly 33 to become effective to move it to the position shown. The position of the throttle valve remains unchanged.

This invention is an improvement upon the structure taught in United States Letters Patent 1,583,959, issued May 11,. 11926,, to H. D. Church. Church teaches. the concept of. achoke structure. they initial movement of. which, partially opens the throttle valve. This structure has, been found inadequate for moderncarburetors if used, merely to secure vfast idling, or for warm-up purposes since even the slightest movement of the choke necessary to open the. throttle causes too rich a mixture to be produced. Applicants structure avoids in this manner the. di'fficulty of. attempting to adjust a carburetor so that. it will give a single mixture suitable forboth a warm. and a cold, engine.

From the above description it will be seen, that an apparatus whereby-a. limited amountof throttle control canbe incorporated into avehicular choke without. interfering with the normal operation of the choke has been provided.

We claim asour invention:

1. In an internal combustion engine carburetor, a. choke valve, a chokevalve operating lever movably mounted, uponsaid carburetor, a movable throttle stop. carrying. membermounted on said carburetor, said choke valve operating lever being mechanically connected to both said. chokevalve and said throttle stop carrying memberso that the initial movement of said operating. lever moves said throttle valve toa predeterminedopen position without. moving, said. choke valve and further movement of said operatinglever moves said choke valve towardsits. closed position.

2. In an internal combustion engine carburetor, a choke valve, a choke valve operating. lever movably mounted on said carburetor .andmechanical- 1y interconnected with a throttle stop carrying leverso. that the. initial, movement of the choke operating lever from; the open towards the; closed position will partiallyopen thev throttlevalve, and

said choke valve operating lever and choke valve being mechanically interconnected so that substantial movement of the choke valve operating lever from the open towards the closed position occurs without causing movement of the choke valve from the full open position to effect an increased idling speed by use of the choke lever without. movingthe choke valve from its fully opened position.

3. In an internal combustion engine carburetor, a choke valve, a choke valve operating lever movably mounted on said carburetor and mechanically interconnected with a throttle stop carrying lever so. that the initial movement of the choke operating lever from the open towards the closed position will partially open the throttle valve, and said choke valve operating lever and choke valvebeing mechanically interconnected through a lostmotion device so that substantial movement of the choke valve operating lever from the open towards the closed position occurs without causing; movementof the choke valve from the full open position to efiect an increased idling speed by use of the, choke lever without moving the choke valve, from its; fully opened position.

4., In an internal combustion engine carburetor, a, choke valve, a choke valve operating lever movably mountedonsaid carburetor and mechanically interconnected with a throttle stop carrying lever so that the initial movement of the choke operating lever from the open towards the closed position will partially openthe throttle valve, and said choke valve operating lever and choke valve being mechanically interconnected through a pin and slot so thatsubstantial movement of the choke valve operating lever from the open towards the closed position occurs Without causing movement of the choke valve from the full open position to efiect an increased idling speed by use of the choke lever without moving the choke valve from its fully opened position.

JOHN P. STUDNICKY. ALPHONSE S. RICK.

REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 1,018,164 Chapin- Feb. 20, 1912 1,139,851 Dayton May 18, 1915 1,209,990 Nevins Dec. 26, 1916 1,887,386 Westover Nov. 8, 1932 2,124,777 Hunt July 25, 1938 2,140,776 Tri-sler Dec. 20, 1938 2,325,372 Coffey July 27, 194.3 2,339,867 Mann Jan. 25, 1944 2,420,917 Sutter May 20, 1947 

